Implementation of a Battery-Free Wireless Sensor for Cyber-Physical Systems Dedicated to Structural Health Monitoring Applications

This paper addresses the concept of a wirelessly powered and battery-free wireless sensor for the cyber–physical systems dedicated to the structural health monitoring applications in harsh environments. The proposed material architecture is based on a smart mesh wireless sensor network composed of sensing nodes and communicating nodes. The sensing nodes are used to sense the physical world. They are battery-free and wirelessly powered by a dedicated radiofrequency source via a far-field wireless power transmission system. The data collected by the sensing nodes are sent to the communicating nodes that, between others, interface the physical world with the digital world through the Internet. A prototype of the sensing node—using a LoRaWAN uplink wireless communication and temperature and relative humidity sensor—has been manufactured, and the experiments have been performed to characterize it. The experimental results prove that the periodicity of measurement and communication can be controlled wirelessly by using only the wireless power transmission downlink. In this paper, we highlight the performance of this complete implementation of a wirelessly powered and battery-free wireless sensing node—not yet integrated or miniaturized—designed for implementing complete cyber–physical systems and based on the simultaneous wireless information and power transfer. Finally, an investigation of comparable implementations of the battery-free sensing nodes for the cyber–physical systems is carried out.